Silicone hydrogels are typically formed by curing blends of silicone monomers or macromers and hydrophilic monomers. In many cases, the blends of the desired silicone monomers with hydrophilic monomers are not miscible. The immiscible blends are opaque and cannot be used to form a material suitable for use in a contact lens.
One solution to the problem of immiscible blends involves the use of specialized diluents, including secondary and tertiary alcohols as well diluents which balance solubility and hydrogen bonding parameters.
Previous attempts to address the immiscibility problem rely on compatabilizing otherwise insoluble blends so that optically clear lenses can be formed. These attempts generally do not provide a beneficial effect on other characteristics of the reaction mixture such as viscosity, rate of curing or the mechanical properties of the resulting contact lens.